1. Field of the Invention
This invention relates generally to mixing devices, and more particularly to a static mixing device for mixing plural flowable components of a composition by combining, subdividing and recombining streams of the components moving along a flowpath from a source to a discharge. The mixing device includes a disposable static mixing conduit formed of flexible material providing a baffled, circuitous flowpath, a reusable rigid support structure for the conduit and a reusable link structure for providing a secure coupling between the conduit and the source of the flowable components.
2. Description of the Prior Art
Static mixing devices are known in the art with fixed structures partially obstructing the flow of materials in a stream flowing through the device. In order to pass the obstructions the materials must follow a circuitous path, which causes eddies and the like and mixes the materials more thoroughly than is possible where material streams from plural sources are carried along an unobstructed passage. This is particularly true for relatively viscous materials, the mixing of which may otherwise require extensive kneading of the materials, e.g., in a flexible bag.
An example of such a device is disclosed in U.S. Pat. No. 4,952,068--Flint, the disclosure of which is hereby incorporated. The conduit therein is formed from opposing sheets of material defining a flexible multi-component squeeze container. Seams join the perimeters of opposing sheets to form a flexible container, with at least one internal wall dividing the container into at least two storage compartments for storing the flowing components before they are brought together for use, and at least one internal wall further downstream for mixing. External pressure on the container forces the plural components to combine in an initial mixing area along a flowpath in the container, downstream of the walls defining the storage compartments. The downstream dividing wall (or walls) is positioned between the initial mixing area and a container outlet. The stream of flowing materials separates and recombines one or more times prior to exit from the container, which provides improved mixing as compared to a substantially laminar flow through an unobstructed conduit.
Normally, a mixing structure as described is used once and discarded. If the mixed components are, for example, a curable resin and a curing agent, material remaining in the mixing structure will harden and obstruct the flowpath. Therefore, the mixing structure is generally not made particularly durable, nor is it associated with an applicator structure that might facilitate application, such as an applicator blade.
A major advantage of a flexible mixing structure is that it can be substantially emptied of material, for example by compressing the mixing structure proceeding from the source toward the discharge end. A rigid structure which cannot be compressed in this manner retains material along the mixing flowpath. Assuming, for example, that the mixed components include a curable resin and a curing agent, any material which remains in the mixing conduit hardens there and is wasted, as well as rendering the device unfit for further use. On the other hand, there are certain advantages to more rigid structures such as their durability and ease of attachment to a source container (e.g., with a threaded neck), their capability to be used as an applicator, etc.
It would be advantageous to provide an improved mixing dispenser in the form of a flexible mixing conduit with durable means to be attached to a source of plural flowable components, such as a multi-component sealant cartridge, for mixing components as they are dispensed. It would also be advantageous to employ a support structure that can facilitate kneading as well as compression of the conduit to empty it, and can be used as an applicator blade or the like, but which is not wasted after a single use.